1. Field of the Invention
The present invention relates to a polymer actuator that includes an electrolyte layer and a pair of electrode layers provided on both surfaces of the electrolyte layer and is bent when a voltage is applied between the pair of electrode layers.
2. Description of the Related Art
Inventions relating to a polymer actuator are disclosed in Japanese Unexamined Patent Application Publication No. 2008-148452 and Japanese Unexamined Patent Application Publication No. 2008-211916. A polymer actuator includes an electrolyte layer and a pair of electrode layers provided on both surfaces of the electrolyte layer.
Further, when a voltage is applied between the pair of electrode layers, the polymer actuator can be bent.
However, it was found that an ionic liquid is exuded from the surface of the electrode layer with the movement of ions between the electrolyte layer and the electrode layers when the DC drive of the polymer actuator is performed or the polymer actuator is driven with the waveform of a voltage having a very long cycle.
When the ionic liquid is exuded from the surface of the electrode layer as described above, conductivity between the electrode layer and a terminal part for applying a voltage to the polymer actuator deteriorates. For this reason, there has been a problem in that the operation of the polymer actuator deteriorates or, in the worst case, the polymer actuator does not operate.
Further, adverse effects, such as corrosion, oxidation, and dielectric breakdown around the polymer actuator, have occurred due to the exudation of the ionic liquid from the surface of the electrode layer.
Furthermore, it was found that the exudation of the ionic liquid particularly occurs on the surface of only one electrode layer and mostly does not occur on the surface of the other electrode layer when the polymer actuator is bent in one direction.